Tinker Just can’t get the concept through my head. What’s the difference in hitting a 37 inch 5 iron or shutting down a normal 7 iron? Can you hit a high fade with that single length 5 iron when it’s called for? If the shortened long irons make hitting them easier why would you lengthen the short irons? Bryson probably swings 37 inch irons 90 plus mph with a crazy Moe Norman swing, can amature do that? What happens to that long iron line drive on an uphill approach? Does anything over a 7 iron land and stop on the green?
1.) Shutting down a normal 7 iron drastically changes turf impact and overall swing. Not the same as swinging a 7i length 5i.
2.) Yes, you can hit any shot with any of these irons as long as you can hit that shot with your 7i.
3.) The goal isn't to lengthen the short irons, but that does happen when you're going single length. The benefit is consistency of every aspect of the swing - stance, club weight, lie angle, ball position, etc. The ball may fly a little higher and a little longer. Easy to adjust, and you can flight the ball down if you feel the need.
4.) I don't recommend anyone try swinging the way Bryson does. One does not need any particular swing to play single length.
5.) The low loft irons do fly slightly lower with perfect contact than a longer low-loft iron with perfect contact. The trade off is that you are likely making better contact more often with the shorter, Single-Length low-loft iron. For most, they'd probably average longer, better shots with the shorter 5i than their conventional 5i. With the right technology, the extra speed needed to elevate the 5i at shorter length is negligible. Further, even if it's a "line drive" (it's not) a low shot hit well is better than a crap shot.
6.) Are you asking if the 4, 5, 6 can stop on a green? Sure! If you can't stop a SL 5i on a well struck shot, I doubt you're stopping the conventional 5i either. But, you'll probably make better contact more often with the SL and give yourself the best chance to hit a quality shot.
It's not like you can give a dink a set of SL irons and they'll suddenly be a great golfer. It removes variables, makes all the irons swing the same, introduces incredible consistency in feel and movement and improves quality of shots as a result. Your best possible shot with a conventional 5i may be superior to the best possible shot with the SL 5i, but you're not giving up much, and your AVERAGE shot with the SL 5i is likely much better than your average shot with the conventional 5i. It is a lot easier to hit any iron when every iron requires the exact same move from the exact same stance.